It is quite common for a photographer to intentionally expose a film at a speed faster than the speed for which the film was designed. For example, a photographer may expose a slow film at a faster speed at an athletic event, in order to photograph a participant or an object in rapid motion. In such instances, the exposed film will be developed for a longer time in order to compensate for the comparatively small amount of silver that was exposed. In color reversal processing, the prolonged development occurs in the first development, i.e. in the black and white development step. However, in many instances when such "push" processing is used, a mismatch of colors occurs in the resultant image. The degradation of color balance arises from differences in the relative developability of the three color sensitive layers in the film. For example, push processing can result in less speed gain in the green sensitive layer, resulting in an objectionable magenta color balance.
In the prior art, it is quite common for a color record in a color reversal film to achieve a speed by push processing which is different from the speed that is achieved by normal processing. This invention comprises the discovery that, when an efficacious amount of colloidal silver is in a layer that is operatively associated with a silver halide-based, light sensitive layer in a color record, push processing will confer a speed on the record, which is faster than that which would result if the colloidal silver layer was absent. The colloidal silver can be in a layer having a hydrophilic dispersing agent, such as gelatin.
Prior to this invention, it was not known that colloidal, elemental silver can overcome problems caused by push processing. In other words, it was not previously known that colloidal elemental silver in a color reversal film could reduce or eliminate color mismatches that result from black-and-white development of color reversal material for a prolonged time.
The improvements of this invention are considered to be a significant advance in the art. The invention provides photographic elements that have good push processing characteristics. This discovery was unexpected. Furthermore, the improved elements of this invention are readily prepared from known materials. In addition, the development methods of this invention are akin to those which are commonly employed throughout the world. Hence, this invention is readily adaptable by both the film manufacturing, and the film processing industries.